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MEYLAN Sandrine - Professeur(e) des universités
Sorbonne Université - Faculté de Sciences - iEES Paris - Bât 44-45, e étage, cc 237
4, place Jussieu
75005 PARIS
Tél Pro :
+33 1 44 27 27 33
Département de recherche IEES
Niveau d'enseignement
- Master 2
- Master 1
Equipe de recherche IEES
Site (campus)
- S-U - P&M Curie - Bât. 44-45 et bât. 44-34
Thèmes de recherche
Maternal effects : hormone and offspring life history traits
Hormones are an important interface between genome and environment, because of their ability to modify the phenotype. More particularly, glucocorticoids are known to affect both morphological, physiological and behavioral traits. Many studies suggest that prenatal stress (associated with an elevation of corticosterone) has deleterious effects on offspring, an altered physiology resulting in retardation of fetal growth and higher percentage of dead neonates. So I conducted several experimental studies on the effect of an elevation of corticosterone in female common lizard during pregnancy on female physiology and offspring characteristics. I demonstrated that this prenatal stress had a profound impact on juvenile traits. Indeed, in male juveniles, survival was higher for juveniles from corticosterone-treated females than from placebo females. Thus, corticosterone does not seem to have detrimental effects on offspring survival, suggesting that it may have an adaptive function.

Adaptive modulation of stress response
In response to stressful conditions, animals modify their behaviour and physiology to avoid or balance negative effects of stress. My works aim to demonstrate that the stress-response mediated by corticosterone is an adaptive mechanism in common lizard (Lacerta vivipara). I experimentally showed that corticosterone increases energy expenditure, daily activity, food intake, males survival and it modifies the behavioural time budget. My studies suggest that corticosterone promotes behaviours that reduce stress and that corticosterone per se does not reduce but directly or indirectly increases longer-term survival.

Immune system
Immune defences are of great benefit to hosts, but reducing the impact of infectious organisms by mounting an immune response also entails costs.  However, the physiological mechanisms that generate these ultimate costs of the immune response remain poorly understood by ecologists.  Moreover, the majority of studies investigating consequences of an immune challenge in vertebrates have been conducted on endotherms.
The aim of my works is to investigate the physiological costs of mounting an immune response in an ectothermic species, the common lizard, Lacerta vivipara. Indeed, because ectothermic species are unable to internally regulate their body temperature, the apportionment of resources to self-maintenance activities including immune function can differ from endothermic species. My studies revealed that mounting an immune response affects reproductive effort through litter weight, but also homeostatis behavior through basking behavior and metabolism.Moreover, I have demonstrated the modulation of the immune challenge impact by intrinsic factors such as corpulence and size, in accordance with the allocation principle.

Publications on : http://ecologie.snv.jussieu.fr/smeylan/sandrine-publications.html
Mots-Clefs
Hormone - Traits d'histoire de vie - Stress - Effet maternel